I think that it would be fair to make distinction based on hardware models not on the store you used to buy the ereader. I bought mine from US and it is totally compatible with the firmware.

You are right, but speak of "models" is difficult, I think. I didn't know if the names given by the stores is the real name of the model. The model of my M92 is "BOOX M92", bought on http://www.ereader-store.de .

The difference known between this model and the "pearl black" of ArtaTech is the firmware. I don't know if the model is something else than "BOOX M92".

It will be useful if the owners of M92 give the model's name and the store where they bought the device.